Air brake



Patented Aug. 9, 1932 UNITED STATES PATENT oFFicE HENRY BIGKEL, OF PLAINFIELD, NEW JERSEY, ASSIGNOR TO THE NEW YORK AIR BRAKE COMPANY, A. CORPORATION OF NEW JERSEY AIR BRAKE Application filed October 20, 1930. Serial No. 490,006.

This invention relates to air brakes, and particularly to the construction of an equalizing discharge valve and its actuating piston used in engineers brake valves to control the discharge of air from the brake pipe in service applications.

The difficulties incident to overcharge of the equalizing reservoir are well understood. To overcome this difliculty in commercial practice, recourse has been had to the plan of Further, the upper portion of the cylinder bushing is subject to greater wear than the lower portion, so that a slight shoulder is developed in the bushing, and the piston is subject to a resulting resistance against initial downward motion to the venting position. If scale lodges in the upper end of one of the venting ports, the rise of the equalizing piston may be prevented. It is then impossible to make a service application.

It has also been proposed to use a spring loaded check valve which offered a one-way restricted passage from the equalizing chambertothe brake pipe, and served to dissipate the overcharge. The present invention relates to this general type, but offers certain improvements in the form and location of the parts. These improvements result in better operative characteristics and render pistons embodying the invention interchangeable with those now in commercial use, even those pistons which are yieldingly mounted on their valve stems, and without changing the cylinder bushing. V

The spring loaded check valve is specially constructed to minimize the tendency of scale to obstruct the closing motion of the valve. Further, it is so located as to minimize the tendency of scale to pass to the valve seat.

Another important feature is the location of the valve in such a manner that the equalizing discharge valve and piston are in static balance about their common axis. This eliminates any canting tendency and insures a smooth free action.

Of great practical importance is the fact that the check valve structure is so mounted and dimensioned that the improved piston is interchangeable with pistons constructed according to existing standards.

A preferred embodiment of the invention is illustrated in the accompanying drawing, in which the single view is a vertical axial section of an engineers brake valve of known form, showing the improved equalizing discharge piston and valve in position.

Engineer brake valve bodies are ordinarily constructed in four parts, a pipe bracket portion l,'equalizing discharge cylinder portion 2, the rotary valve seat portion 3, and the cap portion 4.

The valve shown is a standard commercial type and need not be described in detail. The following parts will readily be recognized:

5 is a main reservoir connection. 6 is a discharge nipple for brake pipe air. 7 is a seat for the equalizing discharge valve, the valve proper being indicated at 8. 9 is the equalizing discharge piston. 11 is the rotary valve and 12 is a portion of the spindle by which the rotary valve is turned.

' It will be understood that the rotary valve has several positions, among which may be mentioned, release position in which main reservoir air is delivered to the brake pipe without reduction of pressure. At such time main reservoir air is furnished to the equalizing chamber, which is indicated by the numeral 1.3, and is the space above the equalizing discharge piston 9. The volume of this space is enlarged by the usual equalizing reservoir, not shown in the drawing. The

space .14 below the piston 9 is always in communication with the brake pipe.

The rotary valve has a second position known as running position, in which main reservoir air is fed at. reduced pressure through a feed valve to the brake pipe. an equalizing port connects the equalizing chamber 13 with the brake pipe so that if the valve remains in running position long formed on its inner face with a sharp enough, equalizing chamber pressure will equalize with brake pipe pressure.

In lap position, all ports in the rotary valve are closed. I11 service position the equalizing chamber 13 is vented ata restricted rate to atmosphere, the purpose being to establish in the chamber 13 a reduced pressure which will cause the piston 9 to rise and open valve 8 until brake pipe pressure falls to a. value slightly lower than equalizing chamber pressure. At this time piston 9 will move down and close the valve 8 against the seat 7.

The rotary valve has other positions, but it is deemed unnecessary to discuss these.

Considering now the equalizing piston 9 and its valve 8, it will be observed that the stem 15 which carries the valve 8 is connected with the piston 9 by means of a hollow hub ortion 16-formed with lateral vents 17 open- 1ng into the brake pipe space beneath the piston 9. The hub 16 extends above the piston 9 and is threaded as indicated at 18 to receive a centrally ported cap 19. The central port is circ ular seat 21 against which seats a ball check valve 22, preferably formed of non-corrosive steel alloy. The angle of the seat is substantially-90 and a line radial to the ball substantially bisects the angle so as to minimize the tendency to arrest oil or dirt. The upper face 20 of'cap 19 is crowned, as indicated in the drawing, and is raised adjacent the central port to form an annular rim 30 around the port. This construction minimizes the accumulation of dust and scale on the valve, the crown 20 and rim 3 directing air upwardly and around the orifice 19, thereby preventing deposition of dust within the orifice.

The valve 22 engages a recess in a spring seat member 23. The spring seat 23 has a reduced portion which receives one end of a coiled compression spring 24, whose other end seats in the lower end of the hollow hub 16. This arrangen'ient has several advantages. The piston 9 and stem 15 are integral with each other,with the result that the piston is guided in the best possible manner within its bushing 25. The piston and all connected parts are in static balance with reference to the axis of the stem 15 and hub 16.

Valve seat 21 offers a very narrow area of contact with the ball 22, and the ball 22 is free to rotate, as it will occasionally do, under the effects of vibration and air flow, thus presenting a changingsurface to the seat. The port leading to the valve seat 21 is located a substantial distance above the upper surface of the piston 9, an arrangement which min- At such time .sipate the overcharge.

imizes the tendency of oil, scale or other solid particles to pass to the seat of the ball valve.

ton were rigidlylconnect'ed together and no means other 'than'the equalizing port and leakage past the piston were afforded to disso equipped are now in service. It may also be substituted for pistons of the type in which the piston is slidably mounted on the valve stem. Where such pistons are used, the bushing 25 is grooved, the groove serving as the vent port. The position of such groove on grooves is indicated in dotted lines at 26. It will be observed that, when the improved piston here disclosed is used, the grooves are below the limit of downward travel of the piston packing ring so that they do not function. V

It should be observed that if the overcharge is to be effectively dissipated, the spring 24 Many brake valves must be quite light. Ordinarily it will be so I chosen that the pressure in the equalizing chamber 13 can exceed the pressure in the brake pipe space 14" by approximately two poundsper square inch. The construction is such as to give adequate length to the spring 24 to insure smooth free action.

The invention produces an equalizing piston and valve mechanism which is inexpensive to construct, which has no parts subject to excessive wear, which is devoid of any cantin or tilting tendencies, and in which the checfi valve is of the self-clearing type. These advantages are attended with the important commercial advantage of complete inter-, changeability with existing standard pistons and valves.

What is claimed is p 1. The combination with a brake valve of the type having anequalizing chamber, a

shiftable valve and ports controlled thereby through which fluid is supplied to the brake pipe and equalizing chamber in running and release position, and discharged from the equalizing chamber in service position, of an equalizing discharge valve mechanism comprising apiston subject in opposingdirections to brake pipe pressure 2. The combination with a brake valve of the type having an equalizing chamber, a shiftable valve and ports controlled thereby through which fluid is supplied to the brake pipe and equalizing chamber in running and release position, and discharged from the equalizing chamber in service position, of an equalizing discharge valve mechanism comprising a piston having an enlarged hollow hub extending above and below the piston, a discharge valve carried by said hub at its lower end, a seat for said valve, the valve and seat controlling discharging flow from the brake pipe; a narrow-edged seat at the upper end of said hub and controlling a passage from the equalizing chamber to the brake pipe; and a ball check valve and spring enclosed in said huband coacting with said narrow seat.

3. The combination defined in claim 2, further characterized that the ball check valve is free to rotate and its seat is a sharp approximately 90 angle edge, the 90 angle being approximately bisected by a line radial to the ball.

4. An equalizing discharge piston having a stem; a valve chamber formed on said stem; and a check valve in said chamber and controlling flow through said piston, the

" parts being so arranged that the piston structure as a whole is in static balance with reference to the axis of said stem.

5. An equalizing discharge piston having a stem; a valve chamber formed on said stem; a check valve in said chamber and controlling flow through said piston; and means on said stem for directing dust away from said valve.

In testimony whereof I have signed my name to this specification.

HENRY F. BICKEL. 

